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4-1: ATOMIC STRUCTURE (page 104-110) Atoms are made up of 3 types of subatomic particles: _________________—positively charged, mass of about 1 a.m.u., located in the nucleus. _________________—have no charge, mass of about 1 a.m.u., located in the nucleus. _________________—negatively charged, very small mass—about 1/1800 the mass of a proton, located in the electron cloud around the outside of the nucleus. The Nucleus The small, dense, _____________ charged center of the atom. Contains _______________ and _______________. Contains 99.9% of the atom’s mass. About 1/100,000 the size of the entire atom. (Think of a _________ in the center of a football stadium!) Outside the Nucleus Danish scientist Niels Bohr said that electrons moved in set paths around the nucleus, similar to the way the ___________ orbit the ________. Later, scientists said that instead of being in definite paths around the nucleus, there were locations where electrons were likely to be found. This region is called the ___________ ___________. Within the electron cloud, electrons with different amounts of energy exist in different __________ __________. Within each energy level, electrons are most likely to be found in regions called ___________. There are four different kinds of ___________: ____, ____, ____, and ____. The simplest kind (“s”) has a shape like a ____________. An electron in the outermost energy level of an atom is called a ___________ ____________. These ____________ electrons determine the chemical properties of the atom. 4-2: A Guided Tour of the Periodic Table (page 111-119) Periodic Law—states that the repeating _____________ and ____________ properties of elements change periodically with the elements’ ___________ ____________. Examples: ̶ Copper, silver and gold are all in the same vertical column on the periodic table. These elements have similar properties: all are good conductors of heat and electricity, all are malleable. ̶ He, Ne, Ar, Kr, Xe and Rn are all gases at room temperature, they do not react with other substances easily. Horizontal rows on the periodic table are called _____________. The number of protons and electrons in the elements increases by one as you move from left to right across one of these rows. Example: Going from left to right in the 4th period, K has 19 protons and electrons; Ca has 20 protons and electrons, etc. Vertical columns on the periodic table are called ______________ or _____________. Atoms of elements in the same vertical column have the same number of ____________ _____________, and so these elements also have similar _______________ ________________. Example: Going down group 17: F, Cl, Br, I, and At all have 7 ___________ ____________. Atomic Number—the number of ____________ in an atom’s nucleus. The symbol used to represent atomic number is ______. All atoms of a particular element have the same atomic number. Examples: All hydrogen atoms have __ ___________ in their nucleus, and thus have an atomic number of 1. All _________ atoms have 82 protons in their nuclei, and thus have an atomic number of 82. Typically, the number of protons in an atom equals the number of electrons in the atom. Therefore, we say that atoms are ________________ charged. Atoms are considered to be chemically stable when they have their valence shell completely full of electrons. Atoms can gain, lose, or share their electrons in order to get a full valence shell. When an atom either gains one or more electrons or loses one or more electrons, the atom is no longer neutrally charged. When an atom or a group of atoms has either a negative or a positive charge it is called an _________. Isotopes—atoms of an element that have the same number of protons as another atom of that element, but have a different number of ____________. Example—isotopes of hydrogen: protons--white Protium Nucleus neutrons--grey Deuterium Nucleus H-1 Tritium Nucleus H-2 H-3 Mass Number and Average Atomic Mass ___________ ________ ________ (amu)—unit used to measure the masses of subatomic particles. Mass Number—the sum of the ____________ and ___________ in an atom’s nucleus. Remember: this means ADD them!! Mass number is always a whole number!! Examples: One isotope of carbon has 6 protons and 6 neutrons in the nucleus. Its mass number is 12 (6 + 6 = 12) Another isotope of carbon has 8 neutrons in the nucleus. What is its mass number? An atom of some element has 11 protons and 13 neutrons in the nucleus. What is the element? ______________ What is its mass number? _________ Average Atomic Mass—the weighted ____________ of the masses of the naturally occurring isotopes for an element. This is the number that appears on the periodic table in each element’s block. Average atomic mass is usually not a whole number. Example: the average atomic mass for: Mg is _____ amu; B is ______ amu 4-3: Families of Elements (page 120- 128) Elements are classified into 3 groups: • Metal (define it)— Where are metals found on the periodic table? List 5 examples of metals. • Nonmetal (define it)— Where are nonmetals found on the periodic table? List 5 examples of nonmetals. • Semiconductors also known as ______________ (define it)— Where are semiconductors found on the periodic table? List the 6 semiconductors your book mentions on pg. 127. METALS—there are 3 categories of metals: • __________ ___________—these metals are found in Group 1. List the elements in this category. List a few physical and chemical properties of elements in this category. How many valence electrons do the elements in this category have? • ____________ _________ __________—these metals are found in Group 2. List the elements in this category. List a few physical and chemical properties of elements in this category. How many valence electrons do the elements in this category have? • _______________ _________—one of the elements found in Groups 3-12 List 5 of the elements in this category. • Some elements, such as technetium and promethium are ____________. Non-Metals • _____________ —these non-metals are found in Group 17. List the elements in this category. List some physical and chemical properties of elements in this category. How many valence electrons do the elements in this category have? • ____________ __________ —these non-metals are found in Group 18. List the elements in this category. List some physical and chemical properties of elements in this category. Why are elements in this group unreactive? How many valence electrons do most elements in this category have? Semi-Conductors • What is the main use of semi-conductors? 4-4: Using Moles to Count Atoms (pg. 129-134) Mole (define it)— List some other counting units (other than the mole) that you know of: How many individual items are in each of the counting units you listed above? How many individual items are in one mole? What is this number called? Molar Mass (define it)— Example: The molar mass of silver is 107.8682 g/mol. Use a periodic table to find the molar masses of the following elements: Ca Cu Xe Be Ba An element’s molar mass can be used as a conversion factor to convert moles to grams or grams to moles. Example: What is the mass of 2.7 moles of neon gas? 2.7 mol Ne 20.1797 g 1 1 mol Ne = 54.49 g Ne How many moles of mercury are in 150 g of Hg? 150 g Hg 1 mol Hg 1 200.59 g Hg = 0.7478 mol Hg Do the “Practice” problems on pg. 133 and the “Math Skills” problems on pg. 134 of your textbook. STUDY FOR YOUR TEST ON CHAPTER 4!!!